- Reported
-
- Issued
-
- Package
-
lopdf
(crates.io)
- Type
-
Vulnerability
- Categories
-
- Keywords
-
#dos
#stack-overflow
#recursion
#untrusted-input
#pdf
- References
-
- CVSS Score
- 7.5
HIGH
- CVSS Details
-
- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Unchanged
- Confidentiality Impact
- None
- Integrity Impact
- None
- Availability Impact
- High
- CVSS Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Patched
-
Description
lopdf::Document::load_mem (and the other load* entry points) parses nested PDF arrays and dictionaries with unbounded recursion. A small crafted PDF whose Catalog contains a deeply nested array (/X [[[ … ]]], on the order of 10,000 levels) exhausts the call stack and aborts the process with SIGABRT.
Because this is a stack-overflow abort rather than a panic!, it cannot be caught with catch_unwind: any service that parses untrusted PDF input with lopdf can be crashed by a ~21 KB file, resulting in a denial of service.
Confirmed on lopdf 0.41.0 and earlier; fixed in 0.42.0. Default configuration, no features changed.
Proof of concept
fn main() {
let bytes = std::fs::read("poc.pdf").unwrap(); // ~10,380-deep nested array in the Catalog
let _ = lopdf::Document::load_mem(&bytes); // stack overflow -> SIGABRT
}
An equivalent PoC is a minimal PDF whose Catalog /X value is "[" * 10380 + "]" * 10380.
Suggested fix
Enforce a maximum object-nesting depth in the parser and return an Err instead of recursing without bound.
Advisory available under CC0-1.0
license.